Chamath tied exceptionally warm sea surface temperatures (SSTs) in the North Atlantic and off Florida to an increased probability of severe tropical storms and hurricanes in the remainder of the 2023 Atlantic season.

Observations back this up:

• NOAA reported that the North Atlantic had record‑warm SSTs and a prolonged marine heatwave beginning in March 2023, conditions that "contributed to a very active 2023 Atlantic hurricane season." (climate.gov)
• The 2023 Atlantic season produced 20 named storms, 7 hurricanes, and 3 major hurricanes, with an Accumulated Cyclone Energy (ACE) of about 146–148. The 1991–2020 averages are ~14 named storms, 7 hurricanes, 3 major hurricanes, and ACE ~123–125. Thus, storm quantity and total energy were clearly above average, even though the number of hurricanes and major hurricanes was near the long‑term mean. (en.wikipedia.org)

NOAA and independent analyses characterize 2023 as an above‑normal, very active Atlantic season, explicitly linking that elevated activity to record‑warm SSTs. (climate.gov) Given that his prediction was about elevated probability of severe storms in a season with anomalously warm SSTs (not a specific count), the subsequent above‑normal activity and energy in the 2023 Atlantic hurricane season align with his claim. Therefore, the prediction is best judged as right.