History. 3 of 7: Wilson in 1919 (day 53), Reagan in 1987 (day 24) and Obama in 2015 (day 49) vetoed a bill of the new Congress within 56 days of its first sitting. The other four took 109 to 154 days.
Hunch. Trump told supporters he will veto anything that hurts America, and the Guardian reported on 8 November that his team is ready to refuse concessions to the new Democratic majority.
The 1 March market resolves on the US Senate list of Trump vetoes and the bill page on congress.gov: YES if by 28 February 2027, Washington time, Trump vetoes, including by pocket veto, a bill or joint resolution of the new Congress that first meets on 3 January. A veto of a bill passed by the old Congress does not count, and the Guardian, BBC News and NPR are the backups.
We looked for cases where the party opposed to the president had just won both chambers of the US Congress, and counted the days from the first sitting of that new Congress to the president's first veto of one of its bills. Since 1919 this has happened seven times. Each of those presidents used a veto in the first year. (US House of Representatives; US House of Representatives; American Presidency Project)