Given two integer arrays `nums1` and `nums2`, return an array of their intersection. Each element in the result must be unique and you may return the result in any order.

Example 1:

    Input: nums1 = [1,2,2,1], nums2 = [2,2]
    Output: [2]

Example 2:

    Input: nums1 = [4,9,5], nums2 = [9,4,9,8,4]
    Output: [9,4]
    Explanation: [4,9] is also accepted.

Constraints:

- `1 <= nums1.length, nums2.length <= 1000`
- `0 <= nums1[i], nums2[i] <= 1000`