If you do not want to use solder iron, then here is an alternate method:
- Apply liquid flux on the pads of the IC.
- Apply some solder on the pads and then place the IC carefully in place, and
- Use the hot air blower/heat gun to secure it firmly in place.
PS: Where your IC pads are, I can see some capacitors and other components. So, you'll have to use your heat gun very carefully.
I'd personally prefer to solder this IC than relying on heat gun to do the job. If the heat gun displaces the caps while placing your IC correctly, re-placing those caps would be much tougher later.