I'd recommend starting some kind of chemical exfoliater. If you're having issues with blackheads, usually a BHA is a good start for that.
As for the pores, I don't think there's actually a way to reduce them, but a BHA can clean them out to make them less noticeable.
If you do get a chemical exfoliater, I'd also recommend moisturizing and hydrating your skin so your moister barrier doesn't get compromised. Over-exfoliation can make things worse and damage your skin in the long run if you're not properly taking care of it.
Also, the blackheads on your nose are typically called "sebaceous filaments". These are pretty much just pores filled with sebum, and they're naturally occurring. The BHA can help reduce the appearance of them and clean them out, but I don't think there's a way to completely rid of them. Some of the BHA's I've used are Stridex in the red box, Cosrx blackhead power liquid, and The Ordinary's salicylic acid 2%.
I hope some of this was helpful, and sorry it was so long. We should really have a pastebin or something for some of this info if we're going to call this a general.