Announced during GDC, the Wii U’s “Nintendo Web Framework” allows developers to use HTML5, Javascript, and CSS to make apps that can run on Wii U, supporting both GamePad and Wiimote controllers
A more directly game-focused tech developers can use is Unity. The popular multiplatform development environment is available for Wii U as well, Nintendo revealed. Both of these technologies are advertised on Nintendo’s GDC site, which also offers links to the developer questionnaire for those interested in becoming licensed Nintendo developers.