It's generally considered polite and respectful to address someone by the name they prefer to be called. If someone has expressed a preference for a particular nickname, it's best to use that nickname when addressing them. Using their preferred nickname shows that you respect their preferences and that you are attentive to their comfort.
On the other hand, using their first name when they have expressed a preference for a nickname might come across as dismissive or inattentive to their feelings. Some people may not mind, but others might find it rude or irritating.
Of course, it's essential to remember that different individuals have different preferences, and some might not be as sensitive about this issue. The key is to be attentive to what the person has told you about their name preference and to follow that in your interactions with them.
If you are unsure about how to address someone, it's perfectly acceptable to ask them politely about their preferred name or how they would like to be addressed. This shows that you care about getting it right and respect their identity and preferences.