Same error using Pytorch 1.7.0 / torchvision 0.8.1 packages in Python, and ‘org.pytorch:pytorch_android:1.7.0’ / ‘org.pytorch:pytorch_android_torchvision:1.7.0’ as dependencies in Android.
The log message explaining that torchvision::nms op may not be currently supported seems to be contradicting the  up-to-date Pytorch 1.7.0 doc 3
EDIT: Torchscript op sets are not the same on PC and android. Nms is indeed included in torchvision and supports scripting but is unavailable in the android version of pytorch (<= 1.7.0)