Usuthu recently re-signed the big striker on loan from Mamelodi Sundowns.
Ntuli, who spent the previous three seasons on loan at Dikwena, scored six goals in 13 outings for Usuthu during a loan spell in 2014/15.
The 27-year-old played for two years under Johnson at Stars, helping the club finish third on the log in 2015/16.
"I've worked with Bongi before at Platinum Stars. He was always a plus to my teams," said Johnson about Ntuli, who travelled with the squad for tonight's clash with Bidvest Wits.
"I know what he's like, I know what he gives to the teams he plays with. Hopefully he's able to do that this year at AmaZulu."
Meanwhile, the former SuperSport United coach expects a tough assignment against the log leaders this evening at Bidvest Stadium.
AmaZulu recorded their biggest win of last season with a 3-0 rout of Wits in Durban in September 2017. The match will be remembered for Students striker Hellings Mhango spitting in the face of Michael Morton, who was sent off for a retaliatory push on the Malawian.
Johnson's side lost the return fixture 3-2 after giving up a lead in the second half.
"It's going to be a tough game, we know that Wits don't give away anything at Bidvest Stadium," he said.
"Gavin Hunt is a very good coach. He has assembled some very good youngsters this season and it is no wonder he got three wins out of three in the opening games.
"So we got to be very careful going up to Johannesburg. We got to make sure that the least we come back with is a point. If we are able to do that then it's going to be a plus.
"We've got our work cut out for us, but I'm sure they feel that they got their work cut out against us too. So it's a two-way stream and football is football ... you never know what will happen on the night."
Johnson is still without winger Ovidy Karuru and defender Sadat Ouro-Akoriko due to injuries.