You cannot boil food that was left out overnight and make it safe to eat.
Food that was left out overnight can grow bacteria quickly and some bacteria that grows on the food overnight produce toxins which are not destroyed by boiling or cooking
Certain bacteria like staphylococcus and Bacillus cereus produce toxins which are not destroyed by boiling or high cooking temperatures.
Never leave any cooked meats or other perishable foods out of the refrigerator for longer than 2 hours as it can make you sick.
It is not safe to leave any cooked meat including canned chicken, cooked fish or other cooked meat out overnight.
Raw meats including raw chicken, beef, fish etc should not be left out of the refrigerator or freezer longer than 30 minutes or it can spoil and grow bacteria.
Raw meats will last 6 months to a year in the freezer but only a few days or so in the refrigerator.
Throw out any meat even if it was cooked if it was left out overnight or for a few hours.
The risk is not worth it and it can make you really sick and can even kill you in some cases.