Before the expression is said by a guy, he previously says the following sentence. I'm not sure if it is related to Kansai dialect.
しっかりしてんかいな ほんまに 無｛む｝計｛けい｝画｛かく｝なことされるのいちばんきらいや。
Another question: Does the 「無計画なことされるの」 mean something not being planned?
Yes, it is unmistakably Kansai.
「こわあてかなわんで」, in Standard Japanese, would be:
「怖{こわ}くて敵{かな}わないよ」. = "I'm scared shitless!"
「敵わない」 = "unbearable", "beyond one's power", "can't do", etc. Remember this word because you will keep encountering it.
Moving on..
「無計画{むけいかく}なことされるの」
「の」＝「こと」. It is a nominalizer, nominalizing the verb phrase 「無計画なこと（を）される」.
「される」, of course, is the passive voice form of 「する」.
"getting haphazard stuff done to me"
