I'll go for
1. FRA
2. BEL
3. NED
4. USA
5. GBR
But everything depends on the starts, the shape of the riders and a good portion of luck. These will be the top five teams anyway. It could turn either way around. Desalle and Van Horebeek need good starts and Lieber needs to stay on two wheels. Been crashing a bit too many lately. France is solid with or without Ferrandis, as is USA. Covington can be podium material in Open Class, but can DNF too. Netherlands has Herlings, but Bogers has been blowing hot and cold the last few races. GBR have a solid team aswell, but I don't know exactly what to expect. Anstie was dissapointing last year but that was an MX2-bike. Searle has to grow to his best form, but I don't know if he will pull it off. Wilson will be decent in top 10 I think.
Throw in Cairoli, Seewer, Bobryshev, Gajser and Jasikonis (if the two latter make the A-final) and Tonus if he gets fit. They can all "steal" important points from the top 5 countries.