Make the Nachos
Season the chicken thighs with salt, pepper, and garlic powder.
Add the oil, coating all the chicken thighs in it.
Add the seasoned chicken thighs to a pan over medium-high heat and cook for about 5-7 minutes. Then flip and cook until the chicken is cooked through (when the chicken reaches the temperature of 165°F (75°C) as measured with a food thermometer). This will obviously vary depending on the size and thickness of the chicken thigh fillets. The ones in the picture below took about 7 minutes on each side.
After it’s cooked, set it aside for a couple of minutes to cool just enough so you can shred it with two forks (as pictured below).
Turn the oven on to 390°F (200°C or 180°fan) and let it preheat while assembling the nachos on a sheet pan.
Assemble the nachos: half the tortilla chips, half of the refried beans, half of the shredded chicken, half of the sliced jalapenos, half of the shredded cheese, and then repeat for the second layer.
Bake in the oven at 390°F (200°C or 180°fan) for 7-10 minutes until the cheese has melted.
Make the Guacamole
Scoop up the avocado and add it to a large bowl with salt, pepper, lime juice, and garlic.
Using a masher or a fork, mash the avocado until you have the desired consistency. I prefer mine to be a bit chunky.
Add the finely chopped onion, cilantro, and tomato, and mix everything lightly until combined. Taste and adjust the seasoning (adding more lime juice, salt, or garlic, if you want).
Add the 'Cold' Toppings to the Nachos
Remove the sheet pan from the oven, and then add your remaining 'cold' toppings. I added scoops of guacamole and some sour cream.