How can I check my .nif model for errors?

[Pershing]

Hi. First of all, I'm a complete newbie in terms of Fallout modding, so please forgive me if I've done something obviously dumb. But yeah, I've made a little armor mod for my body type using NifSkope and Bodyslide. There are both replacers and add-ons. I've made it by copying armor parts to my body .nif, and then fit the meshes and Zap invisible parts in Bodyslide. It looks fine in the game, no missing mesh/textures, no clipping issues, no weird/missing bones. Really the only problem I experience now is that from time to time, when I equip certain armors in PipBoy my game CTDs instantly. It is both for replacers and add-ons so I believe it's not a problem with ESP file. My question, how and where to look for problems? Plz guys help, 'cause I really like my stuff and don't want to have to always remind myself to save before I change the clothes in game ;c

[Neutron_rus]

i have never worked with body slide, but from my experience, it can be like 6 possible things
1. something wrong with your skeleton file (broken skeleton) or bones in the outfit files (missing or wrong bones)
2. wrong settings in the materials of the mesh parts
3. model have some sort of physics colliders (ultra rare thing in case of outfits)
4. too many polygons
5. esp file still can be a problem
6. something not related to your files at all(it's a rare thing too, but sometimes it might happen)

without actual files, it's hard to say