The question was asked, "In Colossians 2:14 what was nailed to the cross?".

Here's the verse:

WEB Col 2:[14 ]wiping out the handwriting in ordinances which was against us; and he has taken it out of the way, nailing it to the cross;

Paul often says very similar things in his different letters, repeating himself in slightly different words, like the "sing" passages in both Ephesians and Colossians.

He's likely saying the same thing in Col 2:14 that he says in Eph:

WEB Eph 2:[14 ]For he is our peace, who made both one, and broke down the middle wall of partition, [15 ]having abolished in the flesh the hostility, the law of commandments contained in ordinances, that he might create in himself one new man of the two, making peace; [16 ]and might reconcile them both in one body to God through the cross, having killed the hostility thereby.

Whatever he's talking about in Ephesians is probably what he's talking about here in Colossians.

To be specific, the Gentiles were unwelcom in the Commonwealth of Israel, unless they submitted to the law of Moses and the Jewish customs (compare Acts 15:1,5).

That requirement has now been taken out of the way, because the full keeping of the law which Jesus accomplished is applied to "believers" (as opposed to failure-prone "Law-keepers", who, at 99.9% success are still failures):

WEB Rom 10:[4 ]For Christ is the fulfillment of the law for righteousness to everyone who believes.

(That righteousness includes baptism, by the way, which Jesus underwent in order to fulfill all righteousness.)

The requirement to keep the law has been taken away; Gentiles can now be grafted into the root, to become full members of the Commonwealth of Israel, by following in the steps of the faith of Abraham, which he had while having not yet been circumcised (Rom 4:12).