可以先计算每个嵌套链表内索引值之和，再利用快速排序算法对链表进行排序。具体实现代码如下：

public class ListNode {
    int val;
    ListNode next;
    ListNode(int x) { val = x; }
}

public ListNode sortLinkedListOfLinkedList(ListNode head) {
    if (head == null || head.next == null) {
        return head;
    }
    ListNode pivot = head;
    ListNode curr = head.next;
    ListNode left = null;
    ListNode right = null;
    ListNode temp = null;
    while (curr != null) {
        if (getSum(curr) < getSum(pivot)) {
            if (left == null) {
                left = curr;
                temp = left;
            } else {
                temp.next = curr;
                temp = temp.next;
            }
        } else {
            if (right == null) {
                right = curr;
                temp = right;
            } else {
                temp.next = curr;
                temp = temp.next;
            }
        }
        curr = curr.next;
    }
    if (temp != null) {
        temp.next = null;
    }
    ListNode leftSorted = sortLinkedListOfLinkedList(left);
    ListNode rightSorted = sortLinkedListOfLinkedList(right);
    if (leftSorted == null) {
        return pivot;
    } else {
        temp = leftSorted;
        while (temp.next != null) {
            temp = temp.next;
        }
        temp.next = pivot;
        pivot.next = rightSorted;
        return leftSorted;
    }
}

private int getSum(ListNode head) {
    int sum = 0;
    ListNode curr = head;
    while (curr != null) {
        sum += curr.val;
        curr = curr.next;
    }
    return sum;
}