Heat butter in a medium saucepan over medium heat. Add onion and garlic.
Cook, stirring occasionally, until onions are tender but do not brown. Add cumin and cayenne pepper and cook until fragrant.
Stir in all but ¼ cup of the milk and bring to a bare simmer.With the remaining ¼ cup of milk whisk in the cornstarch until smooth.
Add cornstarch slurry to pot and whisk it through. Whilst simmering, continue to whisk and cook the cornstarch into the mixture for 2 minutes until thickened and mixture coats the back of a spoon.
Turn off the heat and switch to a spatula. Adding a handful at a time, sprinkle in the cheddar and stir until it is fully dissolved.
Do not add too much at a time. If you need to increase the heat switch the burner on to the lowest setting to help the melting along. Continue adding the cheese until it has all melted.
Cover the queso with a lid while preparing the rest of the nachos.
For the nachos:
In a large sauté pan, cook onion in a drizzle of olive oil until tender. Add the garlic and Mexican spice and cook until fragrant.
Add the mixed mushrooms and cook until they are just tender and going golden brown.
Pour in the tin of chopped tomatoes and bring to a simmer. Add in the drained beans and stir.
Add in the shredded chicken and allow everything to cook together for a few minutes for the flavours to develop and the tomato base to thicken. Arrange a few tortilla chips on a platter or tray.
Reheat queso gently.Layer mushroom mixture, tortilla chips andqueso so that with every bite you get a little bit of everything.
Keep leftover queso in the pot to stay warm and gooey for extra dipping!
Gather the family and friends and serve nachos with guacamole, sour cream, tomato & onion salsa, fresh coriander and some grilled corn!
*If you want to make your own quick and easy Mexican spice mix and you have these spices in the cupboard just whisk them all together! 1 tsp ground cumin1 tsp smoked chipotle flakes1 tsp dried oregano1 tsp smoked paprika