Preheat oven to 225°C (437°F) with fan/convection setting. Brush a baking sheet with oil.
Place chicken thighs on the sheet, brush with oil, and season with salt, pepper, sweet paprika, and rosemary.
Bake for 10 minutes.
While the chicken bakes, peel and halve the potatoes. Peel and quarter the onions. Brush vegetables with oil and season with salt, pepper, paprika, and chopped rosemary. Thinly slice the lime.
Remove the sheet from the oven and add the potatoes, onions, and lime slices around the chicken.
Return to the oven and bake for 40-50 minutes, until chicken is cooked through (74°C / 165°F in the thickest part). If desired, baste with pan juices halfway through.