Not really. It's quite good approach in this context, but not generally.
Because "imediatamente" and "immediately" are not affected by time. But "now (agora)" and "right now" (agora mesmo) can only be used in present.
You can't say "now" (agora) in past, nor in future. Only now.
Let's say there is a couple that never owe anything to anyone. They say everywhere "We (always) pay immediately". They don't need to be in the exact moment of the payment to say that. So they could't use "right now".