No rules against this. Schools can use up to $22MM per year from school/athletics generated revenue to pay athletes. Irrelevant if the athletics budget is running a deficit and has to be covered by the general fund. This is fully legal and likely how most schools are now operating.
I would estimate Bradley's full NIL to be in the $1.5MM range at the moment, possibly higher. Most public MVC schools are reporting in the $800k-$1.25MM range right now.