Currently the list of supported secret backends (where supported means they have a full ui that covers most if not all api operations) is limited to kv v1 and v2, cubbyhole, transit, ssh, pki, and aws. We will be adding support for more of these in the future. For now though there is the web cli - its an interface that will let you use most endpoints via the low level vault commands via an interactive prompt in the ui.
After enabling and configuring the nomad engine, the command to generate a nomad token would be ‘vault write nomad/role-name’ where ‘vault is optional, ‘nomad’ is your mount path, and ‘role-name’ is the role name. To access the web cli, click the shell icon in the upper right of the ui nav.