Mount this on the left side of the fan shroud. Use the unused upper left screw hole to attach. If everything fits then I would use a little E6000 glue and attach it to the shroud using the screw. Should be an M3. I designed this to be as minimal as possible and get as close to the shroud as possible. The sensor should be centered on the nozzle at a distance of approx 53mm. This is using a 5V sensor I originally bought for a PRUSA i3 clone based on Thomas Sanladerer's work and I have not tested it.
ADDED: 18mm version. Thanks Rusty1955
DESIGNED IN TINKERCAD. It's rough but effective.
Print without supports.
Added Version 2. Attach to both top screw holes.