You could try with setting a range of tiles. If you pick the upper left corner of your object with x=Sprite.X-Sprite.Width/2, y= Sprite.Y-Sprite.Height/2 (Origin had to be set in the middle of the sprite) and the multiple of the tiles to the sprite: width = sprite.width/tileWidth height = sprite.height/tileHight:
Sprite| Is overlapping Tilemap -> Tilemap|Set tiles at (Tilemap.PositionToTileX(Sprite.X-Sprite.Width/2)),Tilemap.PositionToTileY(Sprite.Y-Sprite.Height/2)) with area ceil (Sprite.width/32) x ceil(Sprite.Height/32) to tile 1
The tile width and height is in this example 32.