Your social security income is included in the tax computation on Form 8960 (Part III).
See https://www.irs.gov/instructions/i8960#en_US_2022_publink10003491
If you didn’t exclude any amounts from your gross income under section 911 and you don’t own a CFC or PFIC, your MAGI is your AGI as reported on Form 1040 or 1040-SR.
