Also, the parameters for distance expressions are (x1,y1,x2,y2), not (x1,x2,y1,y2)
So the correct expression should look like this:
distance(Tilemap.TileToPositionX(tileX), Tilemap.TileToPositionY(tileY), Player.x, Player.y)
Where tileX and tileY are indices of the tile on tilemap.