Resolved according to the same source that Our World In Data uses, which is Ember Climate.
"non-fossil fuel sources" exclude coal, gas, oil, and "other fossil," and include everything else: hydro, bioenergy, nuclear, solar, wind, and "other renewables," all per Ember Climate's categories.
According to these data, electricity production in Terawatt hours (TWh) by source in the United States for 2022 was as follows:
The percentage of electricity production from non-fossil fuel sources for 2022 was therefore 40.48%.
If any of the next 4 years' annualized electricity production data (2023, 2024, 2025, 2026) show that the sum of non-fossil fuel sources makeup a majority of electricity production in the United States, this question resolves YES.
The original Ember Climate data can be found here in an excel sheet. Look for the rows for the United States in 2022, then for Category = Electricity generation, Subcategory = Fuel, and Unit = TWh.
@DavidSavage there are a number of questions about the Energy sector and other sciences that you might be interested in. And you can write your own with the create question button 😉