$('el').text() returns a string, not a DOM node.
If you are already using jquery, why not use $(el).text('new value') instead? Also, I'm not convinced that .nodeValue works that way.
"In cases where there is no obvious mapping of these attributes for a specific nodeType (e.g., nodeValue for an Element or attributes for a Comment), this returns null."
which can be seen by doing:
var x = window.$('password');
x.nodeValue = "something";
console.log(x.nodeValue); // null
Please add an issue and appropriate specification link if this is not the correct behavior.
-- Elijah