In a saucepan, slowly bring the broth and lychees to a boil over medium heat. Reduce the heat to low and cook until the sauce is reduced by about half then let it cool a bit.
Process the broth/lychee mixture in a blender or food processor until smooth; return the mixture to the pan. Add water to berry mixture to thin it out slightly. Cook over low heat, stirring constantly, until the lychee sauce thickens, about 1 minute then cover and set aside.
In a medium bowl, combine the mustard, honey and a dash of sea salt to taste. Coat the chicken evenly with honey/mustard mixture.
Spray glass baking dish with cooking oil spray then slice onion and layer on the bottom of baking dish. Lay the chicken on top of this and bake at 350 degrees Farenheit until done. (Depends upon thickness of chicken - usually around 40 to 60 minutes.
Top with lychee sauce and serve with steamed veggies and rice.