Check this sentence please?

[iaai]

かごを開けたら、ゴキブリでいっぱいだったよ！
'When I opened the basket, it was full of cockroaches!'
Does this make sense?

Also can いっぱいbe used as a なadjective? i.e. いっぱいなかご 'a full basket'

[taikutsu]

ゴキブリがいっぱいいた makes more sense to me, to say there were a lot of cockroaches.

いっぱい（一杯） is actually a counter, and I haven't seen it used in the way you've suggested.

[Javizy]

一杯 (high-low) is a counter for glasses. いっぱい (low-high) means something is full of something. でいっぱいだった would mean '..was filled with..', がいっぱいいた would mean '..there were loads of...' You can't use いっぱい as a な-adjective, but you could say ゴキブリでいっぱいカゴ or something. I also see it used with の before a nouns.