Former England No.9 Hill was delighted with the performance of his young guns behind a dominant pack and backed them to keep firing with Williams currently ruled out with a hand injury.
"Jonny Arr had a great game against Cornish Pirates last week and he backed that up against Nottingham," said Hill, who has also watched Louis Silver and Joel Dudley get valuable game time this campaign.
"It is wonderful for a scrum half to play behind a pack that is going forward and battering people. The presentation and clear outs were excellent in the first half against Nottingham and gave Jonny good ball to play with.
"It's hard work these days, a scrum half has got to get to a lot of rucks with multi-phase games. But he is sharp and I like Jonny. He is a good player who talks well and had a great game.
"Ollie Frost is also a good talent. He likes to attack around the fringes and we are fortunate to have two very good young scrum halves."