If the Law (Heb. Torah) was abolished or nailed to cross then why in the New Covenant does God put His Torah within us and write it upon our hearts?
I assume you are referring to Colossians 2:13-14. “He forgave our sins, having canceled the charge of our legal indebtedness, which stood against us and condemned us; he has taken it away, nailing it to the cross.” You seem to be assuming that the “law” that was nailed to the cross is the Law of Moses. Scholars agree by consensus that the “law” in Colossians 2:13 is not a reference to the Jewish law specifically, but to law in general. In other words, what was nailed to the cross was our obligation to the law of sin and death, or to the law of our consciences (Romans 2) or the law that says we are saved by obligation or the law of works salvation. I believe that salvation by the Law of Moses falls under this broader heading. This is demonstrated by Colossians 2:16-17, in which Paul uses examples from the Law of Moses. He does this because those who are causing problems at Colossae are Judaizers. It was not the Torah that was nailed to the cross, but it was the law ALL humans live under, which is the obligation to perfection in order to come to God.
Jesus said that he did not come to abolish the Law (of Moses, the Torah) but to fulfill it. He certainly did not abolish the Torah–the Old Testament or any part of the Pentateuch.
The Bible does not say that God puts his Torah within us and write it on our hearts. I think that, as with Colossians 2:13-14 you are slightly misunderstanding Jeremiah 31:33 here. Here God tells us that the “law” he will write on our hearts is the New Covenant. It is the “New Covenant” (Jer 31:31) that he will write on our hearts. It is not the Torah or the Law of Moses that he will write on our hearts. It is the Law of Christ (Gal 6:2) that he will write on our hearts, if we understand Jeremiah 31:31-33 correctly. For these reasons, the apparent contradiction you found and ask about is not a contradiction at all, although, with the assumptions you were making, I can definitely see why you thought there was an apparent contradiction.