Funny, mildly touching, and great storytelling overall.
Noelle Stevenson is known in my household as the writer/creator of Lumberjanes and the creator/show-runner of the new She-Ra series on Netflix, although we were not aware of her involvement with the latter until well after show viewing. Nimona predates both of these, created at Stevenson's ripe old age of her early 20's. It shows off Stevenson's storytelling prowess and talent at producing emotional beats. The artwork is not superb, but it is adequate, and particularly effective in emphasizing emotions through body posture (especially the hunched-over, arms hung limply mode of dejection). There is some great comedic timing also ("I'm a shark!"). My then-8-year-old daughter read it before I did, more than once, and thought it was terrific.