I've done repairs like this before.
A few options.
The weakest: Roughen the area with coarse sandpaper, clean it thoroughly, then glue it back on with a 2 part epoxy or JB Weld.
Another option would be plastic welding. I believe the intake is made of glass reenforced nylon, so you'd need a heat gun and nylon 66 filler rod.
My favorite for this type of job is to drill and tap the hole, then use a thread-in brass hose barb. You can add some epoxy to the threads to reduce the chance of it backing out.
If you drill and tap, position the intake overhead, with the hole facing down (chips don't fall UP) and have a helper keep a shop-vac nozzle near the hole. While drilling AND tapping.
You don't want any plastic chips finding their way into the intake, and later into a cylinder.