Place the lentils in a large pot of water. Bring up to a boil over high heat and then reduce to a simmer. Watch them, stirring and tasting occasionally. You want the lentils to have a nice bite, but remain firm and not falling apart.
Meanwhile, mince and chop up the remaining vegetables, tossing in a large bowl together as soon as they are done. Mince the broccoli, including all but the very tips of the stems.
Cut off the chard stems and slice off the rough tips. Cut the stems into thin strips. Stack up and finely mince across.
Trim the beets and peel. Trim the radishes and fennel, too. Cut these round-ish vegetables into thin round slices. Stack up the slices and cut into strips. Finely mince these strips into a small dice.
Dice the carrot similarly but cut into long thin strips to start and then again into a dice.
Strain and cool the lentils under running water. Toss with the minced vegetables and fresh herbs. Drizzle on the oil, vinegar, salt and pepper adding more as needed to taste.
Serve with the chopped nuts and cheese on the side.