To insert a new node with data of element before a node with a given value, we first need to find the node with the given value. Once we find the node, create a new node with the given element and insert it there. If the given value of is not found in the linked list, we can simply return our original list.

Initialize a temporary pointer to head which will be used to traverse the list.
Since insertion will happen before the node with value val, stop the traversal once the data of the node next to the temporary node is equal to val.
Having reached the desired node, create a new node with data of the element.
Now, point the newly created node to the next node and point the temporary node to the newly created node.
Return the head of the modified list.