Can inderal (propranolol) cause insomnia nightmares and trouble sleeping?

Possibly so. Trouble sleeping, as well as vivid and unusual dreams can occur when taking Inderal (propranolol). Worsening of depression can also be a side effect. Other medications and underlying medical conditions may interfere with sleep. You list being on Klonopin - is that being prescribed for anxiety? Persistent mood and anxiety symptoms impair one's ability to sleep, as well as the quality of sleep. Hope this helps.
Yes, not common. During one of the clinical studies of Inderal, (propranolol) there were 16-17.5% rate of unspecified sleep disorders and 2-6% rate of nightmares. The drug also known to cause agitation, which could certainly disturb sleep.