What is this? Deficiency, toxicity or other?

[Meandering_Mind91]

I have these weird crispy dark green (sorta brown) spots showing up and I can't for the life of me figure out what's wrong. This is my first grow so I don't know a whole helluva lot. Please help. My buddy said it might be nitrogen toxicity and maybe even spider mites....

 

[Jack og]

Toxicity would cause tips out to burn, can we get and underside of leaves pic?
It’s showing signs of mold from this view, mites can be viewed from underside