Nexus mods isn’t shady, they inform user regarding data breach. They provide mods and have been serving mods ever since pre 2010 I believe (registered myself on that site back in 2014 ish).
Maybe slightly off-topic, I recommend to use Viva New Vegas guide as based on my testing the game is more stable and suitable base for modding up your New Vegas install, however also check out every mods you are going to install especially older mods pre-2018 (for me) as they sometime aren’t optimized which may makes unstable issue with the game. Hope you enjoy the New Vegas!
For games, you’d rather use game repacks as they sometime provide smaller package for downloading. The most common one are dodi, fitgirls, though other repacker like el amigos, KaOs krew, Mr Dj also available. If you don’t mind ddl, cs-rin.ru and torrminatorr also available.
Avoid IGG-Games they have shady history in case you use public tracker.
remember rtfm! Megathread, wiki, fmhy are available so you can browse easier as provided by the community.