You "can" use a protected NCR/INR in a regulated mod, as long as it is accepting it without error codes or what not.
It's not the ideal battery to use for your mod's optimal performance.
Once you use low resistance atomizers or higher voltages
which will begin to pull more amps from your battery,
performance could become impaired or the battery might complain by becoming overheated.
Protected batteries don't have the "high drain" load current capability that an IMR will have.
in the past trying to read and put all this reg/unreg/protectected straight in my mind
I compared this to (2) anti-virus's installed on the same computer ;
can be done, but will continuously fight for control resulting in poorer performance