Swap Sprites in TileMap during editor Mode

So basically as the title states I'm trying to get the tiles in my tile map to change based on my Perlin Noise values in the editor, so when I change a value the sprite also changes. Here's my GenerateMap() method, it should be noted that I borrowed heavily from Sebastian Lague's tutorials on Procedural Landmass Generation with modifications to allow for sprites. Thank you for your time.

 [System.Serializable]
 public struct TerrainType {
     public string name;
     public float height;
     public GameObject obj;
     public Sprite sprite;
 }

 public void GenerateMap()
     {
         float[,] noiseMap = Noise.GenerateNoiseMap (mapWidth, mapHeight, seed, noiseScale, octaves, persistence, lacunarity, offset);
         GameObject[] spriteMap = new GameObject[mapWidth * mapHeight];
         Vector2[] positions = new Vector2[mapWidth * mapHeight];
 
         for (int y = 0; y < mapHeight; y++) {
             for (int x = 0; x < mapWidth; x++) {
                 float currentHeight = noiseMap [x, y];
                 for (int i = 0; i < regions.Length; i++) {
                     if (currentHeight <= regions [i].height) {
                         spriteMap [y * mapWidth + x] = regions [i].obj;
                         break;
                     }
                 }
 
 
                 positions [y * mapWidth + x] = new Vector2 (-mapWidth / 2 + x + .5f, -mapHeight / 2 + y + .5f);
                 if (!isMapInstantiated) {
                     Instantiate (spriteMap [y * mapWidth + x], positions [y * mapWidth + x], transform.rotation);
                 } else {
                     for (int i = 0; i < regions.Length; i++) {
                         if (currentHeight <= regions [i].height) {
                             spriteMap [y * mapWidth + x].GetComponent<SpriteRenderer> ().sprite = regions [i].sprite;
                             break;
                         }
                     }
                 }
             }
         }