For "gods," read "powerful but finite beings." They are powerless against time both because they will end (like everything else) and also because they cannot prevent what they know will happen. James Blish made the same point with his title, The Triumph Of Time. In that novel, even:
"...an immortal man who flew from star to star faster than light..."
-James Blish, They Shall Have Stars IN Blish, Cities In Flight (London, 1981), pp. 7-129 AT p. 17 -
- is powerless against time. His physical immortality - immunity to disease and old age - enables him to live only until the end of the universe. The Norse gods live until their doom, the Ragnarok, even though a sibyl has already described it in detail to Odin in Voluspa.
The Okies' powers include faster than light travel, the antiagathics and the instantaneous Dirac communicator. James Blish told me that, in the earliest, unpublished, version of an Okie story, the Dirac communicator received messages from the future. However, knowing the solutions before encountering the problems would have been inappropriate for the problem-solving central character of this series. Consequently, this application of the Dirac transmitter - the reception of messages not only from the present moment but also from every other moment in a four-dimensional continuum - was developed separately in "Beep"/The Quincunx Of Time.
If detailed foreknowledge had remained a feature of the Okie continuum, then John Amalfi would have been even more akin to:
Odin knowing in advance the details of the Ragnarok;
Poul Anderson's Time Patrolman Carl Farness knowing exactly when and where he was to betray his own descendants.