Regular bench utility Nikorima got first crack at starting rake ahead of Travis Waddell for Sunday’s NRL clash at Cronulla after McCullough (hamstring) was ruled out for up to six weeks.
“I don’t remember playing a game without Macca to be honest,” McGuire said.
“Kodi is a great impact player but also capable of starting – I have every confidence in him.”
Brisbane are still reeling from the loss of McCullough who went down early in last round’s Suncorp Stadium win against South Sydney.
McCullough was initially diagnosed with a calf complaint, allaying fears of a season ending knee injury.
However, scans revealed serious hamstring damage for the underrated hooker.
“It’s a massive blow. He doesn’t get big enough raps Andrew,” Brisbane fullback Darius Boyd said.
“He would have been playing Origin (for Queensland) by now if he didn’t have someone like Cameron Smith there.
“He goes unnoticed a bit but we all know how well he goes for our team – we will definitely miss him.”
Former Canberra and Newcastle hooker Waddell will make his Broncos debut off the bench as Nikorima’s back-up.
It is Waddell’s second year at the Broncos.
“I have played with Travis at Newcastle and he is a tough character,” Boyd said.
Kiwi international Alex Glenn (hip) returns from injury and slots straight into the starting backrow, relegating Sam Thaiday to the bench.
The jury was out on Glenn after he trained away from the main group on Tuesday after missing last week’s win over South Sydney.
Herman Ese’ese – who made his Broncos debut last week – has not been named but is on standby for Adam Blair.
The Kiwi prop will fight a dangerous contact charge at the NRL judiciary on Wednesday night over an incident in which South Sydney halfback Adam Reynolds feared he had suffered a broken jaw.
Brisbane bench forward Joe Ofahengaue will play on Sunday after accepting an early guilty plea for a careless high tackle on Paul Carter.