Can I loose weight only focusing on nutrition?

Yes. If you are eating less calories than your body burns. Simple, right? Not easy though.
Exercise is great for overall health and any extra movement will help, but you need to eat less calories than your body burns to lose weight. That’s it. It’s not necessary to exercise to lose weight.
Best of luck to you!

You and lose weight just with a calorie deficit. However, you will get substantial health benefits if you add some activity. Is a medical professional telling you not to exercise? If not, it would be great to add some, starting slowing.

Best of luck.

Yes, you will lose weight in a caloric deficit, regardless of exercise. But as the posters before have mentioned, exercising is highly beneficial for overall health. It assists your weightloss from numerous standpoints - including minimizing the loose (sic) skin problem.

I'm not going to say yes or no, but here's my experience. I Started seeing a nutritionist in mid July. I weighed 414 at the time. Today I am at 368 (in 2011 I weighed 350). My Cholesterol, Glucose, A1c are all close to or within normal levels. It's primarily from focusing on nutrition, and changing some long standing bad eating habits. The nutritionist wanted me to keep a food diary so I started using the Myfitnesspal app. When I set it up, I put my weight in and said how much I wanted to lose and how long to loose it, and it gave me something like 2800 kcal per day. That whole 2000 cal standard diet is bogus, everyone has different needs, and not getting enough calories can also cause you to gain weight. It's weird, not eating enough calories causes your body to hoard calories and store them, rather than burn them. The nutritionist was surprised, she said I should be at around 4000 cal/ day! I don't strictly stick to the allotment the app gives me but use it as a guide. Most days i'm actually coming in a few hundred calories under, and feel pretty good, I rarely feel like i'm starving myself. I also drastically increased my intake of water and reduced my intake of Coffee (i drink it black, no sugar) and Tea (also black, no sugar). I've all but eliminated the black  tea, an only drink a couple cups of coffee in the morning and on my two overnight shifts. I had major issues with heat (I was ALWAYS hot and sweaty, and couldn't cool down), that is practically eliminated now. Gastrointestinal issues are about 90% better than they were, and my peripheral neuropathy has improved about 75%. . I'm wearing clothes that I haven't been able to wear in a couple years. Soon i'll be dropping down to the next size.  

It's not strictly a matter of calories in . It's a matter of changing your eating habits. Eating clean food and  reducing your carb and sugar intake. I try to be somewhere around half of what the app tells me I should have in a day, and it's usually not that hard. The carbs are actually the hardest thing for me to cut back  on.  I used to eat big meals twice a day, now I eat smaller, balanced meals  three times a day. For breakfast I try to have a high protein breakfast (10 - 20 mgs) , either eggs, a protein shake or protein bars (I like the thinkthin high protein bars)  I keep a stash of 100 packs of plain cashews or plan almonds in my drawer at work. if I get a little hungry, i will eat one of those. It's a way of tricking your body so it doesn't go back into hoarding (survival) mode, and by only eating plain nuts, it reduces the likelihood of creating cravings. .

I hope this helps you! Good luck!

To add to what AnvilHead said, if one has very bad eating habits, of course changing eating habits can be a way of reducing calories -- I think people should definitely write down or think through how they were eating and understand where the extra calories were coming from. But weight loss is due to eating fewer calories than you burn, period.

Many people find that two big meals works well for them and lose weight on that schedule.

I generally focus on eating a nutrient-rich diet (not hard for me, those are the foods I like most anyway) and not snacking (I tend to overeat and eat when I'm not really hungry if I snack), but that doesn't mean you have to do that to lose. (Never been sure what "clean food" is supposed to mean, I find it an irritating term. Is other food dirty? Are my Thanksgiving brussels sprouts going to get dirty when I cook them with pancetta? Does my turkey get dirty because I like to combine it with mashed potatoes when eating?)

Cutting carbs is also not something anyone has to do to lose weight. I naturally tend to eat lower carb than MFP's default macros and so do, but lots of people lose with higher carbs, and when I lost most of my weight (I went from around 215 to 125), I didn't think about carbs at all, just protein and eating a generally healthy diet.

I did find exercise helpful -- I enjoy it and tend to naturally eat better when I am active, but if you find it easier to just focus on calories, I think that's fine. Exercise of some sort (you can work on just being more active in daily life at first, and it need not mean going to the gym) is important for health but certainly not necessary for weight loss.