Run ./setup.ps1 -p android in the axmol folder, which should install that NDK.

Alternatively, if you want to use a specific NDK version, then edit the .axproj file in the root folder of your project to add the ndk=XYZ. For example, to use NDK r26d, add this:

ndk=r26d+

If you want to set min and target SDKs, also do so in that same file. For example:

min_sdk=26
target_sdk=35

The default values are in {axmol_dir}/1k/build.profiles, as you can see here.