I don't think I would do that if I were you. The point of a QT tank is to be a place where you can view a new arrival for any illness, and treat if necessary. If you put a new fish in a nano tank, and it comes up with ich then you would have to try to get the fish out of the tank (usually this means dismantling the tank, because they hide in the LR), this would be bad for the corals in the tank, and it would put more stress on the already sick fish, by having to move it into another tank and then going through treatment. This is JMHO.