Rinse and pat the chicken dry, then cut into bite-sized cubes.
Toss the chicken cubes with 1 tablespoon cornstarch until each piece is lightly coated; set aside.
In a small bowl, whisk together the oyster sauce, soy sauce, 1 teaspoon cornstarch, 1/2 tablespoon sugar, 5 tablespoons water, and 1/2 teaspoon sesame oil to make the brown sauce; set aside.
Heat 1½ tablespoons oil in a wok or large skillet over high heat. Add the sliced ginger and stir-fry until aromatic, about 30 seconds.
Add the coated chicken and stir-fry until the outside turns white and the pieces are nearly cooked through, about 3–5 minutes.
Add the sugar snap peas (or snow peas), sliced baby carrots, and sliced almonds; stir to combine and cook 1–2 minutes more.
Pour the prepared brown sauce into the wok, stir constantly until the sauce thickens and the chicken is cooked through, about 1–2 minutes.
Adjust sauce thickness with a splash of water if needed, then transfer to a serving plate and serve immediately.