Six of Nicholls' bets were placed on games involving the Suns, however the 19-year-old did not feature in any of those matches.
None of Nicholls' bets were successful, with no evidence emerging to suggest the defender intended to influence the outcome of any of the matches in question.
Stakes totalled $256 across the 10 separate bets.
“The AFL amended its rules relating to wagering in March 2020 to make it clear that Player and Officials would be held responsible for bets that are placed on accounts in their name.” AFL General Counsel Andrew Dillon said in a league statement.
“The AFL, AFLPA, and all clubs provide extensive education and counselling on all matters relating to gambling. There simply is no excuse - if you have a betting account it is your responsibility to ensure that it is not used for betting on AFL matches regardless of whether you place the bets or not.”
Nicholls won't be permitted to feature for the Suns' VFL side across this period, however will be able to train with the club.
“Rhys has cooperated fully with the investigation, put his hand up and understands the rules and why they are in place,” GC SUNS General Manager of Football Performance Wayne Campbell said in a club statement.
“Rhys will prepare for the upcoming season and we as a football club will continue to support him moving forward.”