Depends on the brick, some kinds of bricks like the MCU brick aren't related to NAND and are never safe to attempt (though it would be very hard to brick the MCU these days since Nintendo supposedly fixed the bug that allowed that to happen back in 8.x or so)
My question to you is why are you using an emunand in the first place? With modern exploits, even bricking the sysnand is nearly impossible, and even if it is bricked it's entirely recoverable.