while you could have multiple omnipotent beings at the same time that choose not to interfere with each other, unfortunately that creates a self imposed limitation upon them thus ironically creates a self imposed nigh omnipotent status
With omnipotence their can be no ifs, buts, or, limitation etc. By imposing that rule they add to their power it changes from "I can do anything I want" to "I can do anything as long as it doesn't interfere with the others work" or "I can do anything as long as everyone agrees"
you could make them all have their own reality or realm for them to do as they wish, preventing them from affecting you, but this still imposes a limitation of "I can do anything WITHIN my own realm" and "except in their realm". this would make you Omnipotent in your realm but nigh omnipotent within all realms thus not true omnipotence
In the end if by some miraculous working both/multiple having omnipotence I foresee it ending in one of two ways, they eventually end up using their omnipotence to erase the others from existence, or use it to remove the others omnipotence either to no powers, or to nigh omnipotence by one not wanting the others to mess with something hey did. ending with a power race of who is the most limited, first to limit the others has no limits, then second limited only by first, third limited by first and second, so on and so forth. still ending in only one omnipotent being
It's not that their cant be more then one omnipotent being, its more of how long their can be multiple before the inevitable event brings it back down to one.
I know it may seem both logical in reason and illogical based upon the power set, but them the breaks. The only way to find the absolute truth is find to beings that have omnipotence, make sure they are both omnipotent and not nigh omnipotent (no idea how) then introduce them and see what happens.