"Be sitting pretty" is an idiom that describes a state of being in a comfortable and successful position. There are several synonyms for this phrase that can be used, depending on the context or tone of the conversation. For instance, one can use "be in a good place," "be on top of the world," or "be at the peak of one's career" to convey a positive message. Conversely, "be at ease," "be in the catbird seat," or "be in the driver's seat" are some of the synonyms that depict a situation of control or power. Ultimately, the choice of synonym should depend on the speaker's intent and the message they intend to convey.