How do we answer this question without exposing ourselves as Realtors to liability? We can't steer you, or say certain areas are "nicer" than others without getting ourselves into a bit of a potential jam. Crazy world where we can't state what is obvious. However, if we have a Buyers Agency Agreement with you where we represent you (exclusively as your agent) we are legally bound to represent you. With this we can better serve you the client.
What I can offer (without the buyers agreement) is a blanket respone to your question. First of all there are several "nice" areas. Based on what some of the respondants have said and I agree nice is relative to what is important to you. Qualifiying with price point would help. But since we don't have the luxury of price range: Almost all areas in Sugar Land are nice. The Nice areas include but may not be limited to: If you can buy 1mm+ I would show you Sweetwater area. If you want 500-1mm I would show you...well lots of areas, If you are at 200-500, Sugar Creek, Greatwood, Orchard Lakes, First Colony , Telfair, Riverstone, New Territory etc. If you are less than 200k First Colony's Chimney Stone, or The Highlands, Colony Bend. Less than 125k is gonna be more difficult... but not impossible.
Bottom line is there are a lot of nice areas and price ranges to pick from in the Sugar Land area.
My advice is to choose a Realtor who knows the area well, listens to you and provides solutions to assist in your home selection.
Best of Luck in your home search!