The powerful wideman signed from French club Beziers last week and debuts in the Championship Cup game at Nottingham tomorrow.
Wellington-born Niko, 28, played rugby league as a junior, representing NRL giants Melbourne Storm as well as New Zealand Warriors.
He switched codes as part of the Australia’s Sevens squad before moving to France to play with Section Paloise, Albi and Beziers.
After back-to-back victories over Doncaster Knights, Carnegie can secure qualification into the knock-out stages with another win.
Their hopes are aided by the return of Pete Lucock to captain the side from centre where he is joined by Andy Forsyth, who recently spent time on dual-registration back at former club Leicester Tigers
Because of that, on-loan Wasps player Jacob Umaga is able to switch to full-back at Nottingham after impressing at centre in last Saturday’s win at Doncaster.
Chris Elder, then, moves onto the wing but Mike Myerscough and Matt Smith are both ruled out after suffering concussion last week.
Prop Craig Mitchell is out with a neck injury but captain Richard Mayhew should return soon.
Meanwhile, Doncaster’s hopes of progressing have been dented but they will seek to get back to winning ways in their penultimate tie at Coventry.
However, their newly-promoted opponents have only lost once at home this season, and that was to last season’s relegated Premiership side London Irish.
Still, Doncaster did win 20-19 against Coventry in their first Cup game last month and now seek a repeat, with director of rugby Clive Griffiths making several changes to the side that were unfortunate to lose to Carnegie last weekend.
In the backs, Steve McColl, Cameron Cowell and Dougie Flockhart all return, while Fijian international Henry Seniloli is set to make his first start of the season.
Up front, Rory Pitman, Colin Quigley and Robin Hislop make their way back, with new signing Mike Mayhew ready for his first start since joining the Knights last month.