For me it has to be DirectBet, in-fact that is the only site I use to bet on sports with BTC, have been betting with them since as long as I can remember and never had any problems.
Yeah directbet for me is one of the best also i never had any problem in that site.. so i suggest this site to gamble your money..
I never tried any site like nitrogen sports because dont understand how nitrogen sports works.. directbet is easy to bet after you choosing a team you will get an address to deposit the bet..
And toto parlay in that site can give more odds than other sports betting
..