delay time of 50 - 200 ns from I to O without external clock

If you are satisfied with a rough and indeterminate delay in that range, you can simply add 2 or 3 cascaded registers clocked by the internal oscillator.

On the other hand if you want an exact delay value in that range, and possibly adjusting it, you'll need an external (fast) clock.

For example, if you want an adjustable delay in 20ns steps, you'll need a 50MHz clock.

The delay is still achieved by passing the signal into a chain of N registers, but you must provide some logic to select N.