This is… not the least belligerent way to ask this question. 
But asking about recourse if leadership is behaving inappropriately deserves a good answer in any organization—it’s the sort of question for which you want to have that good answer well before the organization is in crisis.
You should determine whether you actually are talking about the board of the Foundation, which comprises the four people listed here, or a member of one of the community teams listed here.
I was unable to find documented policies about what to do if a member of a community team behaves inappropriately. Speaking for the Moderation Team, if you have a complaint about a moderator, you should direct it to another moderator—RFC 102 makes us solely responsible for our team composition and procedures. Other teams are likely to have their own policies, but similarly I expect that if you reach out to another member of the team in question, they can assist or at least point you in the right direction. (This is complicated by the fact that some individuals are members of multiple teams, and in the case of a general ‘inappropriate conduct’ complaint as opposed to ‘improper execution of their role’, resolving this simultaneously among all relevant teams may not be easy.) In principle, escalating otherwise irreconcilable issues to the Foundation board may also be an approved reporting path. And of course, the Moderation Team is responsible for ensuring that even other community team members maintain a welcoming environment in NixOS spaces, so if that relates to the unacceptable behavior we are your resource.
The Foundation board, per their Roles and Responsibilities document, serve as a conflict arbitration mechanism of last resort—the buck stops there. There is an open PR in the Foundation repository that, if merged, would create a standard for what is considered acceptable behavior for board members, though I note it doesn’t seem to include an explicit recourse if the standard is violated. As with the Moderation Team, the implicit model here might be that the Foundation board is intended to police itself.
I welcome corrections of any misconceptions I’m propagating here. This post is half ‘a researched and hopefully at least half-correct answer is better than silence’, and half ‘I’m less certain about this than I’d like to be, so here’s my best guess and I’ll either get confirmation or I’ll learn something’.