Manpage nvmecontrol(8) lists:
nvmecontrol format [-f fmt] [-m mset] [-o pi] [-l pil] [-E] [-C] <device-id | namespace-id>
The correct switch for the pi option is -p according to sbin/nvmecontrol/format.c:
OPT("pi", 'p', arg_uint32, opt, pi, "Protective information")
PR: 276554