I actually think from young age he wore the same outfit that we see him wear now.We know he had the red scarf in the movie, which was a part of his scout uniform. For the shirt, it actually matches with the background of his childhood home as we see in the background, so I think he wore it since he was a kid for sentimental reasons.Was I the only one to pick the detail?(I'm rather guessing not but...)For the tie, it is an old idea, but it belonged to his dad as stated by the directors themselves on Quora.I *kinda* headcanon that the same goes for the rest of the outfit (the pants and the sunglasses) that they belonged to someone important to him in the past, only that he *may* have a few more of the same with differing size and little to no variation (he has a pair of both shirts and ties in the movie, but they are near-identical) This may seem a bit odd, but it highlights Nick's sentimentality a *bit*, at least.Any thoughts?