Yes, the Nova will need a pollinator as it is not self fertile. You can use a Temple orange, Orlando Tangelo, or Giberillic acid.
Andi

if I do cross pollinate, will the fruit be a hybrid??????

The fruit itself will not be a hybrid, as it is still being produced by your tangelo tree, with its tangelo genes.
If you were to plant the seeds from that fruit, you might get some hybrid plants, and their fruit could be different. As I understand it, though, most citrus produce a good percentage of nucellar "clones", so you might just get another tangelo. =)

if i have ameyer lemon and a marrs orange in a pot, would that work as well???

Neither the Meyers Lemon or the Marrs will pollinate the Nova Tangelo. The pollinator must be a specific type of tangelo or you can use gibberellic acid. The gibberellic acid will cause fruit to be produced with out the use of pollen from a different source. You can purchase gibberellic acid from several online sources.
Andi

A word of caution:
If you use GA, follow the direction. A little out of proportion your plant may go back to juvinilety.