Swap is not part of the Nolus app. Whichever wallet you connect, there is no Swap button in the Account popover, no Swap tab in the transfer dialog and no swap page, and an old swap link opens the home page.
To change one asset into another, convert it in your own Solana wallet, then open the Account popover from the wallet button in the header and use Fund to bring the asset you want into your Nolus account. If the asset you want to convert sits in your Nolus account, bring it back to your wallet with Withdraw first. Fund and Withdraw are the app’s asset-movement tools. See Fund & Withdraw Assets.