Nav Mesh Question

Is it possible to add a nav mesh to this enemy script so that it will avoid walls and not float into the air?

 using UnityEngine;
 using System.Collections;
 
 [RequireComponent(typeof(SphereCollider))]
 public class EnemyAI : MonoBehaviour {
 
     public float preceptionRadius = 10;
 
     public Transform target;
     public float movementSpeed = 5;
     public float rotationSpeed = 420;
 
 
     public bool dontMoveTorwardsPlayer;
     public LayerMask MoveBlockers;
 
 
     public Transform startCast, endCast;
 
     private Transform myTransform;
 
     // Use this for initialization
     void Start ()
     {
         SphereCollider sc = GetComponent<SphereCollider>();
         CharacterController cc = GetComponent<CharacterController>();
 
         if (sc == null)
             Debug.LogError("No Collider on enemy");
         else
         {
             sc.isTrigger = true;
         }
 
         if(cc == null)
         {
             Debug.LogError("There's no Character Controller");
         }
         else
         {
             sc.center = cc.center;
             sc.radius = preceptionRadius;
         }
 
         myTransform = transform;
     }
 
     void FixedUpdate()
     {
         Debug.DrawLine(startCast.position, endCast.position, Color.white);
 
         dontMoveTorwardsPlayer = Physics.Linecast(startCast.position, endCast.position, MoveBlockers);
       }
      
     // Update is called once per frame
     void Update()
     {
             if (!dontMoveTorwardsPlayer)
             {
 
                 if (target)
 
                 {
                     Vector3 dir = (target.position - myTransform.position).normalized;
                     float direction = Vector3.Dot(dir, transform.forward);
 
                     float dist = Vector3.Distance(target.position, myTransform.position);
 
                     //Find or Look at Target
                     myTransform.rotation = Quaternion.Lerp(myTransform.rotation, Quaternion.LookRotation(target.position - myTransform.position), rotationSpeed * Time.deltaTime);
 
                     //Movement
                     myTransform.position += myTransform.forward * movementSpeed * Time.deltaTime;
                 }
             }
         }
                 
     public void OnTriggerEnter(Collider other)
     {
         Debug.Log("Entered");
         if (other.CompareTag("Player"))
         {
             target = other.transform;
         }
     }
     public void OnTriggerExit(Collider other)
     {
         Debug.Log("Exit");
         if(other.CompareTag("Player"))
         {
             target = null;
         }
     }
 }