There is chaos, having nothing to speculate (8)
I believe the answer is:
theorise
'to speculate' is the definition.
(synonyms)
'there is chaos having nothing' is the wordplay.
'chaos' is an anagram indicator.
'having' means one lot of letters goes inside another.
'nothing' becomes 'O' (O resembles 0).
'there'+'is'='thereis'
'thereis' with letters rearranged gives 'therise'.
'therise' enclosing 'o' is 'THEORISE'.
(Other definitions for theorise that I've seen before include "Speculate by reasoning" , "Conjecture, hypothesise" , "Think up possible explanations" , "Express ideas" , "Form of hypothesis or conjecture" .)