As explained in the Q&A Do Nondetection and Invisibility protect you from True Seeing?, the nondetection spell would hide an invisible character from being seen by a creature under the effect of the true seeing spell (though not natural truesight). I am framing my question with the context that true seeing is included among the divination magic that nondetection hides creatures from.
Can someone with the true seeing spell cast on them see someone in the area of a darkness spell that has nondetection cast on them?
To answer this appropriately, I feel an answer must consider this:
Does the True Seeing spell modify your actual sight, or give you a second sight?