Preheat the oil on medium heat in a small pot until it is hot. Line a plate with paper towels. Arrange everything near your stove.
In a bowl mix together the hot sauce, brown sugar, and vinegar. Set aside.
Add the cornstarch to a bowl and season with salt and pepper. Add the chicken and toss to coat well.
Whisk together the eggs in a bowl. Dip the chicken into the eggs and then back into the cornstarch to coat well.
Fry the chicken in the oil until it reaches an internal temperature of 160 degrees using a thermometer (fry in batches if needed being careful to not overcrowd the oil)
When chicken is done, remove it from the pot with a slotted spoon and transfer it to the plate lined with paper towels to drain off any excess oil.
Toss the chicken in the hot sauce and serve. Garnish with scallions.