That 880lbs figure stated in the article clearly won't be the weight of the final product when and if implemented, there are electric motors now a days producing amazing torque at very low weight, there was also a 330lbs figure given in the article, take it to pilots to run with the worst case scenarion
also the weight of the device won't be in addition to the brake assembly for that tire, it will be in lieu off since an electric motor can be utilized as dynamic braking just like it is used today in large trucks and trains, you don't need to install it in all the tires of an A/C as someone suggested that you will need to install 16 in a 747, 3 will be enough, the hardest part for the motors will be the initial break away torque needed, once the weight is rolling the inertia of the mass itself will help along. If this system is used in both the departure and arrival stages, it could be huge savings
Who said anything about the nose gear?