My script to move a gameobject to the closest tagged gameobject doesn't work

I have 2 tagged gameobjects, and I would like a gameobject (which has the script below attached to it) to move to the closest gameobject that has the tag. However, it doesn’t. Please can someone kindly tell me why? Thanksenter code here

using UnityEngine;
using System.Collections;

public class moveBomb : MonoBehaviour
{


	public GameObject object1;
	private GameObject[] objects1;
	private GameObject nearestTarget;
	private float distance;
	private float curDistance;
	private Vector3 pos;
	private Vector3 diff;
	private float speed = 1.5f;


    // Use this for initialization
    void Start()
    {

		nearestTarget = null;
		distance = Mathf.Infinity;
		pos = transform.position;
		objects1 = GameObject.FindGameObjectsWithTag("target");
		FindClosesttarget();


    }

	void FindClosesttarget()
	{
		foreach (GameObject obj in objects1)
		{
			diff = obj.transform.position - pos;
			curDistance = diff.sqrMagnitude;
			if(curDistance < distance)
			{
				nearestTarget = obj;
				object1 = nearestTarget;
				distance = curDistance;
			}
		}
	}



    // Update is called once per frame
    void Update()
    {
		if (object1 != null)
		{
			transform.position = Vector3.MoveTowards (transform.position, object1.transform.position, speed);
		}


    }

    void OnTriggerEnter2D(Collider2D col)
    {

        if (col.gameObject.tag == "target")
        {
            Destroy(transform.gameObject);

        }

   
    }
}

Try using this:

using UnityEngine;
 using System.Collections;
 
 public class moveBomb : MonoBehaviour
 {
     private GameObject[] objects1;
     private GameObject nearestTarget;
     private float distance;
     private float curDistance;
     private Vector3 pos;
     private float speed = 1.5f;
 
 
     // Use this for initialization
     void Start()
     {
 
         nearestTarget = null;
         distance = Mathf.Infinity;
         pos = transform.position;
         objects1 = GameObject.FindGameObjectsWithTag("target");
         FindClosesttarget();
 
 
     }
 
     void FindClosesttarget()
     {
         foreach (GameObject obj in objects1)
         {
             curDistance = (obj.transform.position - pos).magnitude;
             
             if(curDistance < distance)
             {
                 nearestTarget = obj;
                 distance = curDistance;
             }
         }
     }
 
 
 
     // Update is called once per frame
     void Update()
     {
         if (nearestTarget != null)
         {
             transform.position += nearestTarget.transform.position * speed * Time.deltaTime;
         }
 
 
     }
 
     void OnTriggerEnter2D(Collider2D col)
     {
 
         if (col.gameObject.tag == "target")
         {
             Destroy(transform.gameObject);
 
         }
 
    
     }
 }