I'm inclined to believe it just wasn't working out with Artie/Nick and the higher ups decided to go with the bigger star.
And I am an Artie fan boy. I like him, I want to see him do well and I don't think he needs to be on the HSS to be funny. There's been plenty of moments of the new show that I really enjoyed (although seeing him QUITE POSSIBLY STONED in that Dice interview was really depressing).
tl;dr I'm sure Nick has a following but I don't think he worked as a host, no disrespect to him/his fans