My baby girl is 1 year and 1 month old. She no longer wants to sit in a high chair and when we feed her, she always runs off.
Is it ok to chase after her and feed her?
At a guess, your girl has discovered the power of "No". She will not starve herself, so try letting her run away. Ignore her. She will not go far. Then she will get hungry, and will want food and also your attention. Let her have food and attention once she is sitting in the high chair.
Once you have the high chair established you can work on regular feeding times. Do not try to make her eat, but once she decides to stop do not give any more food until the next feeding time. Tell her this; even if she cannot speak, she probably understands quite a bit.
See here for more on this approach: http://peacefulparentsconfidentkids.com/2013/04/six-steps-to-a-peaceful-toddler-meal-time/
You only need to worry if your child is underweight or failing to put on weight. Here are the official (though rather complicated) charts used to decide this. https://www.rcpch.ac.uk/resources/uk-who-growth-charts-0-4-years