A connection to Tor must be made before the tunnel-link (proxy / VPN / SSH): User → Tor → proxy / VPN / SSH → Internet.
It is recommended to add the securely encrypted version of the IRC server, preferably an onion service which uses SSL as a fallback or at best, both.
All servers, besides the secure (SSL) version of the Open and Free Technology Community (OFTC) have been removed. HexChat in Whonix ™ has been hardened according to The Tor Project's Torrifying HexChat guide. It includes basic functionality found in IRC clients, like secure connections, multiple server connections, nick completion, a client-to-client protocol, direct client-to-client file transfer and chat, and a plugin system which allows extension of features and further customization. HexChat is an open source IRC client based on XChat. 2.5 Disabling Hardening and File Transfers.