I don't want my Support license taken up by a Chat user. How do I create a Chat-only agent when I have a Zendesk Support subscription as well?
Creating a Chat-agent only depends on what type of Chat version you use. To determine the Chat version you have, see the article: Determining your Zendesk Chat account version.
Zendesk Chat Phase 4
Create your Chat-only users from your Chat dashboard instead of creating the profile in Support. For detailed instructions, see the article: Creating agents and departments in Chat.
Chat agents will then be added to your Support account as users in the Contributor role. Contributors don't take a Support license. For more information about this role, see the article: Creating custom roles and assigning agents (Enterprise).
Zendesk Chat Phase 3
Create your Chat agent in your Support dashboard. Set the role for the user as Contributor in Admin Center. For more information on how to add agents, see the article: Adding agents and administrators.
Legacy Zendesk Chat + Support
Chat agents for legacy Chat accounts don't take a Support seat by default unless you add the user as an agent in your Support account. For more information, see the article: (Legacy Chat) Creating agents and departments