General "nice":
* अच्छा (achchha): This is the most common and versatile word for "nice". It can be used in many situations.
* सुंदर (sundar): This means "beautiful" and can be used for things that are aesthetically pleasing.
* अच्छा लगता है (achchha lagta hai): This literally means "it feels good", and is used to express that you like something.
More specific "nice":
* प्यारा (pyaara): This means "cute" or "lovely" and is often used for people or animals.
* बढ़िया (badhiya): This means "great" or "excellent" and is used to express strong approval.
* सुहावना (suhaavana): This means "pleasant" or "agreeable" and is used to describe something that is enjoyable.
Formal "nice":
* अच्छा (achchha): This can also be used in formal situations, but you can also use "सुंदर (sundar)" or "अच्छा लगता है (achchha lagta hai)".
Remember that the most appropriate word depends on the context and the specific meaning you want to convey.