How to make the AI Chase you?

Hello guys, I am making a 2D pixel art game where you play as a character and you must pick-up the diamond to progress however there is an evil Zombie who chases you down. I have done everything else fine however I am struggling on making the AI Chase you as I couldn’t find any tutorials.

Any help is welcome! Thanks!!

That is because there cannot be artificial intelligence tutorial at that level.

If I can draw an analogy, the tutorial you may find would be the equivalent of learning how to spell and follow the rules of syntax.

Knowing how your evil Zombie should react is akin to wanting a tutorial on how to write the next best selling novel. You will never figure out how to make a compelling story by reading the dictionary.

Same thing here.
You have to ask yourself: what should the zombie do? Does he chase you in a straight line, irrespective to the presence of obstacles? Does he sense you when you are behind something?
Once you have decided how the zombie should react, what is its strategy, then putting this in code format, with a bunch of IF and ELSE statements, will be you AI.