Well, doing something hard is the way we learn.
If you can do nodal analysis then just do the analysis so that, for a negative feedback circuit, all the currents into the summing (-) junction equals zero.
For example, for a simple inverting op amp circuit with an input resistor Ri and a feedback resistor Rf, then for the current into the summing junction to equal zero, Vin/Rin must equal -Vo/Rf. Translating terms gives Vo/Vin (the voltage gain) = -Rf/Rin (The - means the circuit is inverting). You just do that for any feedback circuit and you will come up with the gain.