It's a TC4429 - makes a difference.
You'll probably be terribly insulted, that I'm trashing your creation, and that's wholly not my intention, but I take particular issue with your grounding in addition to other aspects of your wiring and construction technique.
1. I can't see any wires connected to the drain terminal of the mosfet in your photo. Was the load actually connected during your testing? If so, how was it connected (in particular, where was it connected to the ground line), and how much current does the load take?
2. What is the value of the decoupling capacitor connected between the supply and ground pins of the TC4429?
3. What is the nature of the 12V power supply, and what is its off-load voltage? I'm wondering whether it produces a temporary voltage reversal during startup or shutdown, or alternatively that it produces a lot more than 12V when the load is not energised. Assuming you didn't short the output of the TC4429, there must be something nasty happening on the supply pins to cause it to fail, and this would likely cause any other driver chip to fail too. The Arduino is protected to some extent by the diode you put in series with the Vin pin.
4. Why are you using a switching frequency as high as 32KHz? The higher the switching frequency, the more careful you need to be with circuit layout, to keep the inductance of critical paths low.
To avoid such transients, add a decoupling capacitor between the -ve side of the LED and the source of the mosfet.
QuoteTo avoid such transients, add a decoupling capacitor between the -ve side of the LED and the source of the mosfet.Between pins 1 and 8 of the TC4429, correct?
No, it should be much closer to the mosfet source and the ground side of the LED than that, so that the switching transients don't propagate to the rest of the circuit. I would use 1uF ceramic in parallel with at least 100uF electrolytic.
However, this doesn't explain how you managed to damage a TC4429 when there was no load connected - that puzzles me.
I suggest connecting a resistor of about 220 or 470 ohms between the Arduino output pin and the TC4429 input.
I see, (I assume "the LED" refers to the 8 amps of DC lighting) I will do that.