Tileable perlin noise terrain

I have been trying to make an infinite terrain over the last couple of weeks but I can't make it work, here is my current code:

  function GenerateTile(nw : int, nh : int) {
     if (GameObject.Find("Chunk "+nw+","+nh)) { 
         return;
     }
          
     var freq : float = Frequency;
     var td = new TerrainData();
     td.heightmapResolution = 513;
     td.size = new Vector3(500,200,500);
 
     var ChunkPosX : float = td.size.x * nw;
     var ChunkPosY : float = td.size.z * nh;
 
     var t = Terrain.CreateTerrainGameObject(td);
     var hw : float = Terrain.activeTerrain.terrainData.heightmapWidth;
     var hh : float = Terrain.activeTerrain.terrainData.heightmapHeight;
     var heights = new float[hw, hh];
     for (var x = 0; x < hw; x++) {
         for (var y = 0; y < hh; y++) {
             //           World Pos Divided by heightmap height
             var xCoord = ((ChunkPosX + x) / (Mathf.PI * scale));
             var yCoord = ((ChunkPosY + y) / (Mathf.PI * scale));
             if (x == 0 && y == 0) {
                 Debug.Log(xCoord);
                 Debug.Log(yCoord);
             }
             heights[x,y] = Mathf.PerlinNoise(xCoord, yCoord);
         }
     }
     Terrain.activeTerrain.terrainData.SetHeights(0,0,heights);
     t.transform.position = new Vector3(ChunkPosX, 0,ChunkPosY);
     t.name = "Chunk "+nw+","+nh;
 }