Toast the bagel to your desired level of crispness.

Heat butter in a large nonstick skillet over medium-high heat.

Add the chicken sausage and cook until heated through and lightly browned. Remove and set aside.

Crack the eggs into the same skillet and season with a pinch of kosher salt.

Once the edges are set and the whites begin to turn opaque, flip the eggs and reduce heat to medium-low.

Place cheddar and American cheese on top of the eggs and stack them together so the cheese melts evenly.

Add the chicken sausage on top of the eggs and cheese, then turn off the heat.

Spread the avocado onto the bottom half of the toasted bagel and lightly season with salt.

Add the egg, cheese, and chicken sausage stack.

Spread creamy sriracha sauce on the inside of the top bagel half, close the sandwich, and serve immediately.