Not sure I understand your question since the title says interactive viewport but the text question says interactive renderer.
If you mean renderer, and that you can fiddle settings in Corona while rendering, well you click on Rendering>Render Setup, Common tab, scroll down to Assign Renderer, and select Corona as the Production renderer. Click on Rendering>Render. And while it's rendering, you can fiddle various controls. Most useful for me is the exposure settings in Rendering > Environment and Exposure Settings. Other people here can tell you much more about what can be changed interactively and what can't.
If you want a Corona viewport, now that you have your renderer set to Corona, go to top left in viewport, and click on rendering style, it's probably set to wireframe right now. Click on Realistic. Now that it says Realistic, click on it again, then go to Lighting and Shadows and select Illuminate with Scene Lights. Then click on Realistic AGAIN, and go down to Materials and click on Realistic Materials With Maps. If your textures are still not showing, go to the material editor and select the bitmap(s) and click on the button that says Show Shaded Material In Viewport.
