I decided to play with this a bit.
So instead of the obvious literal "I am good" I decided to answer "I am fine".
But the red tinted correction on the bottom of the page corrected me with "I am nice"!!!
I have some background in using Hindi and I am certain that मैं अच्छा हूँ in everyday speech can be translated as "I'm fine"
In what context would you say this in everyday speech? I would say "main Thiik huu~" if I wanted to say I am fine.
Can you say this in response to the question how are you? or does it simply mean that I am a good person?
My indian friend said it can be used in both situations, but for 'how are you' main theek hoon is used more often!