The ladder-leaders travel to play North Melbourne on Saturday without Rankine, who has been banned four games for a homophobic slur.
The Crows will retain top spot entering the finals with a win over the lowly Kangaroos at Marvel Stadium.
Even with an upset loss, Adelaide will still finish in the top two and host two home finals as they return to the playoffs for the first time since 2017.
"It's next man up," Nicks said when asked how the mercurial Rankine would be replaced.
"We have got guys we believe can play a role for us ahead of the ball.
"It's always going to look a little bit different, it doesn't matter which player you don't have access to, it's always going to change slightly.
"But we're confident in the 23 (players) that we'll take across, that we will have guys step up into that role."
Nicks recalled 19-year-old Sid Draper, 21-year-old Billy Dowling and triple club champion Rory Laird, returning from suspension, to play the Kangaroos.
Draper and Dowling, who both have played only nine AFL games, now have a gilt-edged chance to press their claims for the finals.
"There's a lot of reasons why Sid has come in ... we like his form, the way he's developing," Nicks said.
"This is a great opportunity for him and Billy Dowling ... to show what they've got as we go into a finals series."
With Rankine banned, Nicks also axed Lachie Murphy and Harry Schoenberg.
The 16th-placed Roos, winners just five times this season, have summoned Aidan Corr and Zac Banch to replace forward Cam Zurhaar (ankle) and Matt Whitlock, who has been dropped.
Nicks conceded the challenge to perform after the week-long Rankine furore.
"To our group's credit, they've had a really strong week and focused themselves on what they can impact - and that's the way we play footy," he said.
"We're in a unique position. We've got an opportunity where we've done a lot of work right throughout the year and through past years to get ourselves in this position.
"One of the things we've done so well this year is not look back and not look forward - we have lived in the moment.
"We have played every moment as it comes and it will be a challenge for us to get that right tomorrow."
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