Is there a way to change it to a no chill batch? I.e. Recalculate ibus based on extended times above isomerisatiin temps?
Does any brewing software offer this?
Calculating late additions for no chill is a bit of a dark art, and hard to get from brewing software as there are a lot of variables (cube volume, wort temp, type of hops, ambient temp etc).
Best way is a bit of trial and error to work it out for you're gear and cube sizes.
Most people calculate the IBUs added from cube hops/late hops as somewhere between a 10-20 minute addition.
FWIW, when I make a hoppy beer I put in a bittering addition at 60 minutes (with about 20-30% of the total IBUs), then put a huge cube hop addition to make up the rest of the IBUs + the flavour. I calculate it as a 15 minute addition, and it works brilliantly for my setup (old 17L fresh wort kit cubes). Great smooth bitterness and amazing late hop character.
The other option is do a mini boil with about 5-10L of wort and use that for your late hops (search for Argon's method). You can rapidly chill the wort in a sink of iced water, the strain the cooled wort into a fermenter with the rest of the cubed wort.
You should be able to nail down what works for you in no more than 2-3 brews.
JD