Вот ответ, который я искал.
using UnityEngine;
using UnityEditor;
using UnityEngine.Tilemaps;
public class TileParser : MonoBehaviour
{
private const string inputPath = "Tilesets";
private const string outputPath = "Assets/Tiles/";
[MenuItem("Pre Production/Parse Tiles")]
public static void ParseTiles()
{
var sprites = Resources.LoadAll<Sprite>(inputPath);
foreach(var sprite in sprites)
{
Tile t = ScriptableObject.CreateInstance<Tile>();
t.name = sprite.name;
t.sprite = sprite;
AssetDatabase.CreateAsset(t, string.Format("{0}{1}.asset", outputPath, t.name));
}
Debug.Log(sprites.Length + " tiles created at " + outputPath);
}
}