The lot is cast into the lap, but its every decision is from the LORD. -- Proverbs 16:33 (NKJV)

Out of context it seems like lot casting is contrasted with decisions from God.

"Lot casting" should not be confused with the "national lottery" where the latter's purpose is to encourage greed (Hebrews 13:5) and covetousness (Luke 12:15).

The directly translated Hebrew according to Bible Hub's Interlinear Bible:

Into the lap/bossom/bottom/midst is cast/thrown lot/lot-pebbles used for making decisions/portion but from Yahweh every/all/whole/any/total decision/judgement/ordinance/case/manner/plan

There are no evidence that the practise to find God's will is condemned.

Instead, a more correct translation might be:

People cast lots to learn God's will, but God himself determines the answer. -- Proverbs 16:33 (GNT)

The correct purpose for lost casting should be to end quarrels among believers.

Casting the lot ends quarrels and separates strong opponents. -- Proverbs 18:18 (ESV)

This is evident in the following examples:

• Priests deciding which goat should be used for which purpose or sacrifice (Leviticus 16:8)
• Priests appointing responsibilities (Nehemiah 10:34)
• The division of the land under Joshua (Numbers 26:55; 33:54; 34:13; 36:2; Joshua 18:6-10)
• Israelites agreeing on a battle strategy (Judges 20:9)
• King David's government choosing leaders and responsibilities (1 Chronicles 24:5,31; 25:8-9; 26:13-14)
• The apostles appointing a replacement for Judas (Acts 1:26)
• King Saul determining the guilty party (1 Samuel 14:41)

In addition, gentiles also cast lots in the Bible:

• Jonah (prophet of God) agreed on the outcome of the lot that he is guilty (Jonah 1:7).
• Haman (Persian leader) used it to make his decisions (Esther 3:7).
• Roman soldiers used it to determine who get Jesus' clothes (Matthew 27:35).

Urim and the Thummim

What it was:

And in the breastpiece of judgment you shall put the Urim and the Thummim, and they shall be on Aaron's heart, when he goes in before the Lord. Thus Aaron shall bear the judgment of the people of Israel on his heart before the Lord regularly. -- Exodus 28:30 (ESV)

What it was used for:

And he shall stand before Eleazar the priest, who shall inquire for him by the judgment of the Urim before the Lord. At his word they shall go out, and at his word they shall come in, both he and all the people of Israel with him, the whole congregation. -- Numbers 27:21 (ESV)

Example where the Urim failed:

And when Saul inquired of the Lord, the Lord did not answer him, either by dreams, or by Urim, or by prophets. -- 1 Samuel 28:6 (ESV)

Last recording of lot casting

After the Apostle Judas had betrayed Jesus and committed suicide, Peter explained the problem:

So one of the men who have accompanied us during tall the time that the Lord Jesus went in and out among us, beginning from the baptism of John until the day when whe was taken up from us — one of these men must become with us a witness to his resurrection.” -- Acts 1:21-22 (ESV)

The leaders used their own logic to nominate two possible candidates to replace Judas:

And they put forward two, Joseph called Barsabbas, who was also called Justus, and Matthias. -- Acts 1:23 (ESV)

They did not immediately roll the dice and see how the lottery will come out, instead...

They prayed and said, “You, Lord, who know the hearts of all, show which one of these two you have chosen to take the place in this ministry and apostleship from which Judas turned aside to go to his own place.” -- Acts 1:24-25 (ESV)

They narrowed the options down with their own logic, but the final decision would be determined by information that is impossible for them to reason out with logic or with the facts that they have available to them. This is where they needed divine input to guide them.

And they cast lots for them, and the lot fell on Matthias, and he was numbered with the eleven apostles. -- Acts 1:26 (ESV)

Lot Casting vs Holy Spirit

Some might argue that the above-mentioned Acts 1 event occurred before the Spirit of God was poured out on all flesh and that the Holy Spirit replaces this practise.

When the day of Pentecost arrived, they were all together in one place.

...

"And in the last days it shall be, God declares, that I will pour out my Spirit on all flesh..."

-- Acts 2:1,17 (ESV)

However, in Moses' lifetime the Spirit was already instructing people and this is confirmed by Nehemiah:

You gave your good Spirit to instruct them and did not withhold your manna from their mouth and gave them water for their thirst. Forty years you sustained them in the wilderness, and they lacked nothing. -- Nehemiah 9:20-21 (ESV)

And King David also confirmed this:

Teach me to do your will, for you are my God! Let your good Spirit lead me on level ground! -- Psalm 143:10 (ESV)

Lot casting is not in contrast with the Holy Spirit. Instead, God must be present otherwise you are gambling. Note how the apostles prayed that God should determine the outcome (Acts 1:24-25).

There are no scientific logic behind lot casting, and it requires a huge amount of faith and commitment. You also need to believe that God will determine the outcome (Proverbs 16:33). The outcome might be uncomfortable, so it is important that all parties agree to commit to whatever the outcome will be.

Lot casting is not a quickfix or a solution to seek guidance and advise from the Holy Spirit for everyday problems. The purpose of lot casting is to end quarrels among two or more believers who strongly disagree on a matter (Proverbs 18:18).

The purpose of lot casting was specifically...

• to divide property (Numbers 26:55; 33:54; 34:13; 36:2; Joshua 18:6-10),
• appointing responsibilities (Nehemiah 10:34, 1 Chronicles 24:5,31; 25:8-9; 26:13-14, Acts 1:26),
• decide on battle strategies (Numbers 27:21, Judges 20:9) or
• to point out a guilty party (1 Samuel 14:41, Jonah 1:7)

... to end quarrels.