Cook the peanuts in your preferred way either in the instant pot or the pressure cooker as mentioned above.
Let it cool down and remove the peanuts from the shells.
Now add the chopped mangoes, onions, cucumber, carrot, salt, and red chili powder.
Toss them together.
And that's it; yummy sundal is ready.
Notes
Please add the salt while cooking peanuts. I just added ¼ tsp of salt for the veggies later. But you can adjust both salt and red chili powder as per your preference.
Instead of red chili powder, you can add chaat powder or jal jeera masala or pani puri masala and make it a tangy sundal.
You can add veggies of your choice.
Instead of chopping the veggies, you can grate them too.