@Critter-3 Thank you once again! You've just saved me a lot of trouble and I very much appreciate it.
To confirm the right steps:
1. Input NRA spouse income, foreign tax paid etc. and any other corrections and finalize 2019 amended return in Turbotax first.
2. Take carry forward Tax Credit numbers from 2019 return and input into 2020 return. For me there is the normal carry foward table as well as an AMT version. I had to pay AMT in 2019 when I filed MFS.
(for the past few years I've always had a carry forward amount)
3. File 2020 now by mail
4. File 2019 by mail after ITIN is issued
