No. The cards available through the Chrome Extension are non-reloadable, which means you cannot add funds after the initial load. This is part of why these cards have little to no fee.
If you need a card you can add money to over time, use our reloadable card options on the web app. See the reloadable vs non-reloadable comparison for details.
The extension can still be used to retrieve card details after creation and to complete issuer-required redemption steps. For why U.S./CAD non-reloadable cards must be ordered via the extension, see this explanation.