Peel the chayote, cut off the core and discard, and julienne.
Peel the carrot and julienne as well.
Peel and thinly slice the onion.
Cut the bacon into strips.
Heat a frying pan and spray (or brush) the bottom with cooking oil.
Cook the bacon over medium heat until it has browned and rendered fat. Scoop out the bacon and move to a bowl.
In the rendered bacon fat, saute the chayote, carrot and onion with salt and pepper. Cook over medium heat, with occasional stirring until done but still lightly crisp.
Taste and add more salt and pepper, as needed.
Add the browned bacon to the vegetables. Cook, stirring, until heated through.