Form 1040-NR is for non-resident aliens. I assume you are a US citizen and have been filing Form 1040. Being a US citizen your global income is taxed no matter where you are living in the world. So, that possibily introduces another element to your situation--you said you would only have the Roth conversion income in the US for 2023. If you will be making any money outside the US for 2023, it could be subject to federal taxes.
However, there is also the provision to have your foreign earned income exlcuded from federal taxation if you meet certain criteria, one of them being out of the country for most of the year. There are also limits to how much you can exclude.
Here is some good information from the IRS: Figuring the Foreign Earned Income Exclusion
Again, feel free to call and talk to a tax expert and we would be happy to assist you.
