Currently, it is not proven that $NP \geq O(n \log n)$ in the Turing Machine Model.

The weakness of this statement can be illustrated by NP-complete problems, which we think require way more time. But I'm looking for the easiest-to-solve decision problem in P that probably has $\Omega (n \log n)$ as lower bound in the Turing machine model (I say "probably", because proving it would be a scientific breakthrough). Such a problem would best illustrate the power of the statement "$NP \geq O(n \log n)$".

It inspired me to ask about a candidate: Deterministic linear time algorithm to check if one array is a sorted version of the other, but it may not be the simplest because Yuval pointed out it probably requires more than $O(n \log n)$ in the Turing machine model.