For all intents and purposes these are LOT flights, including the flights on BMI metal from Copenhagen to Gronigen and Örebro. Even meilenrechner.de
shows them as LOT flights.
Nordica does not have its own AOC, so LOT acts as the marketing and operating airline for them. Nordica also uses LOT's booking and check-in systems.
These LO 8xxx flights themselves might be technically operated by:
* LOT's own E175
* Regional Jet's CRJ700 and CRJ900
* BMI Regional's E135/E145
* rarely Carpatair's F100
Regional Jet which owns the whole
Nordica-LOT co-branded fleet was a fully-owned Noridca subsidiary, but now is 50%-owned by the Polish airline. This shows the current LOT-Nordica partnership is stronger than the previous one between Nordica and Adria.
Regional Jet also operates some LOT-branded flights between Warsaw and Stockholm.
As long as this arrangement is in place, LOT has two hubs (major at WAW and minor at TLL).
Also, read
this message on Nordica's website.