Can you block a shot if you are not touching the hive.

Yes, you can block a shot without touching the hive.
According to Q&A 2: Legality of Shot Blockers, blocking or defending shots taken are not specifically disallowed by the BIOBUZZ rules.
Also, Q&A 20: Blocking refers to QA2 and QA8 for the answer, which implies that blocking a shot is allowed.

Sources
- Breaking Down BIOBUZZ Strategies | FTC Live | FIRST Tech Challenge — 15:11 to 17:43 — FUN Robotics Network
- BIOBUZZ Strategy: How to Win Auto, Teleop, and Flowers — 17:35 to 20:08 — Brogan M. Pratt
- This Transfer Makes Holding Too Many IMPOSSIBLE FTC Friday's BIOBUZZ — 15:07 to 17:38 — Brogan M. Pratt
- BIOBUZZ Fouls Explained — 5:01 to 7:32 — Brogan M. Pratt
- Q&A 12: Hive tipping