Things not loading generally indicates problems with your installation of either the basic game or the mods in question. For starters, Did you install Steam to it's default location? (GOG is not a problem as it places the game correctly.) If so, please see the wiki "Installing Games on Windows Vista+" article for why the original default Steam behavior of installing games to the "C:\Program Files" or "C:\Program Files(x86)" folder tree was bad (they learned better, and don't do that any more but didn't change it for older games); and why "disabling UAC and running as Administrator" is NOT sufficient, with instructions how to move it. Among other things, later versions of Windows (since the game was released) force files in "system protected" folder trees to be "read only" regardless of how you set them manually. It includes instructions on how to correctly move the Steam folders out of that folder path.
Don't move it to a folder under "User\Documents" either, as "executable" files are not permitted to run from there for similar "anti-malware" reasons.
This is the single most important thing you can do to fix and protect yourself against problems in the future. As much of a PITA as that is, it's never going to be any easier than now. System updates often cause issues with games installed to these folder trees. With the game moved out of the default location you will not need to be running it as an "Administrator Account", which is safer. Please see the 'Restoring to "Vanilla"' section of the wiki "FNV General Mod Use Advice" article as well.
We REALLY need to see a sorted "load order" (such as produced by "LOOT"); to include the main game and DLC files. (Screenshots don't work so well for the purpose.) With modded games its the sequence, not merely the list of mods, which is the cause of many problems. LOOT's sort gives a good first approximation, correcting the most obvious issues and is sufficient for most players. You can make minor adjustments to the order and tell LOOT how to remember them. It's in the on-line documentation under "Metadata". Instructions on how to copy it's list for posting are in the "How to ask for help" article, and "Checklist Item #11' entry in the wiki "Fallout NV Mod Conflict Troubleshooting" guide.
In the meantime, please see the 'Vanilla Load Order' entry in the 'First Timer Advice' section; as well as the 'Towards Game Stability' and the 'Common Game Problems' sections of the wiki "FNV General Mod Use Advice" article.
I recommend anyone read the entire "FNV General Mod Use Advice" article to understand the differences between this game and others you may have experience with; especially if this is your first attempt to play a modded FNV or it's been more than a year since you last set it up. It is designed for someone who has never played a modded PC game before, so it tries to avoid making any assumptions, is kept "up-to-date", and covers years of "lessons learned" by a retired Technical Support expert. It is NOT a list of various mods to install that happen to work on the author's machine; only "the essentials". It addresses fundamentals underlying how to get the basic game and mods to work together. At least 90% of everything I post in the "Technical Support" sub-forum is already in that article. Once you can play a test game to at least Primm, only then should you try adding other mods from some other "guide".