The goal of Scheme Nomic is to have the bot say <your nickname> is the winner, or something to that effect.
How this goal is acheived is collectively up to you and the other players.
Many 'tricks' are obvious but count as cheating: one person could potentially represent many players, but this is highly discouraged. Same with impersonating a player by using their nickname.
Any sizable cabal can execute arbitrary code. Using this to crash the bot or otherwise cause undesirable and clearly non-gameplay activity is discouraged. It's not clever or well-executed 'hacking' to do so, and effectively, everybody loses. Similarly, one could end the game by flipping over the table while playing Monopoly; this proves nothing but that the table-flipper has working muscles.
Only a given set of nicknames are players at a given time. A player may submit a proposal by saying:
!p <proposal>
where <proposal> is a sexp that will, if the proposal is enacted, be evaluated.
The bot will report the unique number of this proposal.
A player may vote on an un-enacted proposal by saying:
!v [y|n] <proposal number>
The bot will not respond, but the vote (should be) recorded.
If the number of yes votes meets or exceeds a quorum, which is the (number of players + 1)/2, rounded up, one can enact the proposal by saying:
!e <proposal number>
The proposal is then passed to eval to be evaluated. Errors in evaluation are caught, but not reported on; the bot will only notify that there is an error. If there aren't enough yes votes to meet a quorum, this will be stated.