Nikora was charged with a grade two high tackle by the match review committee for the incident in the 77th minute of the Sharks' 22-14 loss to the Dragons on Saturday.
He was also sent to the sin-bin.
The Sharks are seventh on 28 points and still have a bye and three matches, against Gold Coast and Newcastle at home and Canterbury away, in the final four weeks of the NRL season.
Nikora will miss all three with an early guilty plea but risks being rubbed out of the first week of the finals if he challenges at the judiciary and fails.
Cronulla have some chance of sneaking into the top four but the loss of Nikora, one of their chief attacking weapons, will make that task harder.
The four players sin-binned in the Sydney Roosters' 64-12 win over the Dolphins on Saturday night have been hit with fines.
Roosters duo Spencer Leniu and Naufahu Whyte, along with the Dolphins pair Aublix Tawha and Francis Molo, were charged with contrary conduct for their part in a melee that erupted in the ninth minute. Leniu also received a second contrary conduct charge for his role in the fracas.
Leniu will have to cough up $3600 while Molo, Tawha and Whyte have been billed $1000 each with early pleas.
It is worse for Molo as he will miss the derby with Brisbane on Saturday night after also being charged with a careless high tackle on Whyte in the 43rd minute. The grade two charge will mean he misses one week with an early guilty plea.
Dolphins lock Kurt Donoghoe will also have to dig into his pockets and pay a $4800 in fines for a shoulder charge on Leniu and high tackle on centre Billy Smith.
The Dolphins already were set to be without veteran forward Felise Kaufusi for the Broncos clash. He is serving two weeks for a previous misdemeanour.
Sitting eighth on 26 points, the Dolphins are just ahead of the Roosters, also on 26 points, on for-and-against.
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