Could not build module 'nanopb' error in Xcode 12.0.1

All I did was to follow the instruction(see image below) and it got fixed.

Source here

I had the same problem with a project still targeting iOS 8 as the minimum iOS version. This steps solved my problem:

1. Update minimum target iOS version to iOS 9 on Podfile file;
2. Open terminal on project folder, remove all pod file dependencies and update them by running:

rm -rf /Pods
pod repo update
pod install

3. Update minimum project target iOS version to iOS 9;
4. Remove DerivedData;
5. Clean project;
6. Compile/run project again.

A simpler solution is to update cocoapods to the 1.10 version

First, update the CocoaPods installation : [sudo] gem install cocoapods

Then, update your project : bundle update cocoapods

Finally, run pod install and everything should be OK :)