A patient describes a sensation of something moving deep inside his chest, distinct from his heartbeat, rather than on the surface of his skin. Is this a tactile hallucination?

No — this is a visceral hallucination, not a tactile hallucination. A tactile hallucination is a false sensation of touch, pressure, or movement on or under the skin surface (such as formication, a crawling sensation under the skin). A visceral hallucination is a false sensation located inside the body — the internal organs or deep tissue, as described here (deep in the chest, distinct from the heartbeat) — rather than on the skin. Both belong to the same broader family of bodily hallucinations and share the same practical caution (rule out a genuine physical cause first), but they are distinguished by where, specifically, the false sensation is located: surface versus interior.