Hi tal15235,
Are you using the devkit or custom board for Jetson Nano?
What’s your Jetpack version in use?
Please refer to the following thread to enable PWM.
Unable to generate PWM with Nvidia Jetson AGX Orin Development Kit - #6 by KevinFFF
It is the instruction for AGX Orin, but it should be the similar steps for Jetson Nano.