Adding Nested Treeview Nodes in VB.NET?

Assuming that the structure you want looks like:

key1-- key2
   -- key3

the final line should be: TV1.Nodes("key1").Nodes("key2").Nodes.Add("key3", "Test3")

Or with

key1-- key2-- key3

Use TV1.Nodes("key1").Nodes.Add("key3", "Test3")