Although he has not thrown an MLB pitch in 2020, Jimmy Nelson threw 10,406 pitches that were tracked by the PITCHf/x system between 2012 and 2019, including pitches thrown in the MLB Regular Season, Spring Training and Fall/Winter Ball. In 2019, he relied primarily on his Sinker (93mph), Slider (86mph), Fourseam Fastball (93mph) and Curve (83mph). He also rarely threw a Change (87mph).
Basic description of 2019 pitches compared to other RHP:
His sinker has surprisingly little armside run, results in more flyballs compared to other pitchers' sinkers and has slightly above average velo. His slider sweeps across the zone, generates a high number of swings & misses compared to other pitchers' sliders, results in more flyballs compared to other pitchers' sliders and has some two-plane movement. His fourseam fastball is straight as an arrow, has some natural sinking action and has essentially average velo. His curve is much harder than usual, results in many more groundballs compared to other pitchers' curves and has a sharp downward bite. His change (take this with a grain of salt because he's only thrown 3 of them in 2019) is basically never swung at and missed compared to other pitchers' changeups, has surprising cut action, is much firmer than usual, results in more flyballs compared to other pitchers' changeups and has some natural sink to it.