How to get view variable in controller?
and even if I update or change some properties in the variable, the view should update.
How to do this?

I tried:

var someVar = Ext.getCmp('idHere');
//Selecting the third container from the collection of selected containers
var someNestedChild = someVar.query('container')[2];      
someNestedChild.el.dom.innerText = "I need to change this text";
But the above is giving undefined error whenever I add el, dom or body to someNestedChild variable.