Hmm, it's a bit hard to explain I guess. Here are the translations as well as sentences without "nog". Det blir nog bra = That's fine, I suppose. Det blir bra = That's fine. Jag vill nog hellre ha en kopp kaffe tack = I think I'd rather have a cup of coffee please. Jag vill hellre ha en kopp kaffe tack = I'd rather want a cup of coffee please. Det ordnar sig nog = I'm sure it will be fine. Det ordnar sig = It'll be fine. Det ska du nog inte räkna med = I'm not so sure you can count on that. Det ska du inte räkna med = You shouldn't count on that.

tack