Contradiction with Isaiah 28:2
While Nahum 3:12 talks about weakness, Isaiah 28:2 speaks of a powerful and strong one who will destroy.
Isaiah 28:2: Behold, the Lord hath a mighty and strong one, [which] as a tempest of hail [and] a destroying storm, as a flood of mighty waters overflowing, shall cast down to the earth with the hand.
Contradiction with Deuteronomy 28:7
This verse promises that enemies who come will be smitten and flee, contrary to the easy taking of the defenses in Nahum 3:12.
Deuteronomy 28:7: The LORD shall cause thine enemies that rise up against thee to be smitten before thy face: they shall come out against thee one way, and flee before thee seven ways.
Contradiction with Isaiah 41:11
This verse suggests that those against will be as nothing and perish, unlike the falling defenses in Nahum 3:12.
Isaiah 41:11: Behold, all they that were incensed against thee shall be ashamed and confounded: they shall be as nothing; and they that strive with thee shall perish. [they that strive...: Heb. the men of thy strife]
Contradiction with Jeremiah 1:19
Unlike the vulnerability in Nahum 3:12, this verse promises deliverance and overcoming adversaries.
Jeremiah 1:19: And they shall fight against thee; but they shall not prevail against thee; for I [am] with thee, saith the LORD, to deliver thee.