I have seen this repo/video before, and the build system here does exactly that using the latest Android NDK/SDK. There is also a config.nims which is responsible for configuring the right cross-compiler and some more compiler/linker options directly in the module here I've spit everything up purposely and it works quite nicely imo. Also it avoids the gradle build system.
Besides mine, a previous attempt was made here: https://github.com/yglukhov/nimx/blob/master/nimx/naketools.nim using nake but due to the switch to Nimv2, it's currently broken.