The tilemap has some expressions you can use to get that. Namely the row and column of the tile at a certain xy. Then you can use another expression to get the xy of the tile at a certain column and row. That will give you the tiles center then you can get the sides by adding/subtracting half the tile width/height.
But you can calculate all that directly. For example if the tilemap is at 0,0 with a 32x32 tile size, and the player objects are smaller than 32x32, then this will give you the bounding boxes of each of the tiles the player could be overlapping.
Gridx= int(player.x/32)
Gridy=int(player.y/32)
For i=-1 to 1
For j=-1 to 1
Tile at (gridx+i,gridy+j) != -1
— left = (gridx+i)*32-32
— right=(gridx+i)*32
— top=(gridy+j)*32-32
— bottom=(gridy+j)*32
— resolve collision