Certainly possible, there are all kinds of ways to achieve it. Here is a very simple example.
if action.released and action_id == hash("touch") then
if action.x > 0 and action.x < 100 and action.y > 0 and action.y < 100 then
--do stuff
end
end
For GUI, I recommend you read up on gui.pick_node().
See this thread to understand the different types of coordinates returned in an input action.